What Food Cravings and Gila Monsters Have in Common

If you want some help losing weight, you may have an unexpected ally in the Gila monster. Researchers have discovered that the saliva of the Gila monster lizard has the ability to reduce food cravings.

Gila monsters have special saliva

Gila monsters (Heloderma suspectum) are the largest land lizards in the United States, growing up to 2 feet in length and weighing up to around 5 pounds. Their bite, although painful, is not deadly, but it is their saliva that has captured the interest of researchers, and in more ways than one.

The saliva of the lizard contains a substance called exendin-4, which several years ago became the basis of a drug called exenatide, which is a synthetic form of the saliva component. Also known by the trade name Byetta, exenatide was approved by the Food and Drug Administration in April 2005 to help manage blood sugar levels in individuals who have type 2 diabetes.

Now, at Sahlgrenska Academy, University of Gothenburg, investigators conducting a study in rats unexpectedly found that a drug made from the saliva of the Gila monster stopped the animals from craving food and chocolate. This finding was “both unknown and quite unexpected,” according to Karolina Skibicka, assistant professor and one of the study’s authors.

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Skibicka also noted that her research team has “shown that exendin-4 affects the reward and motivation regions of the brain,” which opens the door for several potential applications for this new discovery.

Suzanne Dickson, professor of physiology at the Sahlgrenska Academy, pointed out that exendin-4 could “help obese people to take control of their weight,” while Skibicka noted “it would be very interesting to test whether exendin-4 also reduces the cravings for alcohol.”

Previous research has shown that exendin-4 is a hormone that is about 50% identical to a hormone found in the human digestive tract, called glucagon-like peptide-1 analog (GLP-1). GLP-1 increases the production of insulin when blood sugar levels are high. However, exendin-4 stays effective longer than GLP-1. Earlier research also showed exenatide can reduce appetite, which may lead to weight loss.

The saliva of the Gila monster has triggered the development of a drug that not only helps people with type 2 diabetes manage their blood sugar, but also appears to be effective in stopping food cravings. Fortunately for the Gila monster, which is a threatened species, scientists produce a synthetic form of exenatide for use in Byetta and research like the current one on food cravings.